Fumed Silica is composed of submicron-sized spheres&comma; which are 40-60&percnt; fused into short chains&comma; very highly branched&comma;0&period;1-0&period;2microns long&period; The spheres are quite uniform in size for a given product&comma; but the chain lengths are quite variable&comma;10 to 30 units in length&period; The surface area&comma; which varies with the particle size&comma; gives a good approximation if the sphere diameter&period; The smaller the particles&comma; the larger the estimated surface area&period;fumed silicon dioxide is a hydrophilic fumed Silica with specific surface area of 150m2&sol;g&comma; and it synthetic&comma; hydrophilic&comma; amorphous silica&comma; produced via flame hydrolysis&period; Particle between 7~40nm&period; Along with the traditional polyester&comma; silicone&comma; paints and coatings applications&comma; fumed silicon dioxide are used with increasing success in high technology fields&period; The particle nature and high purity of fumed silica play key roles in the electronics and optical fibers industries&period;